Surgical knives or scalpels are utilized by surgeons in many instances to complete operative procedures. Of course, many such procedures are performed on patients with infectious diseases such as acquired immune deficiency syndrome (AIDS) and infectious hepatitis. Unfortunately, the attending surgeons, nurses and other health care workers are subjected to a significant risk of infection if they are inadvertently stuck, pricked or cut with a contaminated surgical knife that has been withdrawn from a patient inflicted with such a communicable disease. Accordingly, it should be appreciated that it is critically important to avoid accidents including inadvertent sticks and cuts of any individual with a used surgical knife. Further, the safe, long term disposal of surgical knives and particularly used surgical knives is a serious concern.
These concerns have been addressed in the prior art. For example, in U.S. Pat. No. 3,906,626 to Riuli, a disposable surgical scalpel is disclosed including a protective outer sheath and retractable and extendable handle carrying a knife blade. The device also includes a "permanent" locking arrangement including a cooperating detent, spring, and resilient cam. It should be noted, however, that when locked the cam projects outwardly from the sheath. Accordingly, the cam may be engaged inadvertently by an object or individual and accidently manipulated to release the lock thereby allowing the knife blade to again be extended from the sheath. As a result, a significant risk of inadvertent or accidental sticks and cuts still remains in this prior art design. Accordingly, a need exists for an improved arrangement wherein the permanent lock is fully concealed and shielded from inadvertent contact and manipulation.